Ford 4-wire MAF sensor wiring tests (integrity testing)

[@ColeTanner88]

Man, invaluable information here! I've used your bypass testing methods regularly since learning them a couple months ago. But I've always done it with the sensors unplugged. Could've gotten burned on a ford maf sensor issue had I come across one stuck at 0v before watching this video! Love your teaching methods man, can't thank you enough for the information you're passing along. Has saved me time and helped me understand circuitry better. In the past couple months I've grown tremendously from your teachings and even taught ase master techs at work a few things. With your videos/book I'm quickly surpassing the knowledge of my co-workers and now they've begun to ask me questions when they're having issues. Can't get enough of it man, I'm starting to really enjoy troubleshooting now. I thank God everyday for the mechanical ability he's given me and the opportunity to absorb such great knowledge. Keep it up brother, God bless you and your family.

[@GammaCruxis]

Dude - if you don't have your own parking spot, day of the week and bards singing your exploits - it needs to start now. I've learned tons from you short of sitting in your classroom. Thanks for all you do.

[@ScannerDanner]

Agree and thank you! I have seen many times a shorted 5v ref. "come back to life" after repairing the short.

[@tinydx95t2]

Paul I went to school years ago (Vale Technical Inst.) and I've learned more about electrical circuits since I started watching your channel that I did in school. Thanks for educating us.

[@ScannerDanner]

I have done it that way and it works, I just haven't done it enough in all situations to be 100% comfortable with doing that test here.

[@bradensmith888]

I almost replaced the ECM because I was testing ECM MAF ground with the MAF unplugged. Thank you for this video; you saved me $200

[@ScannerDanner]

Glad to help!

[@ScannerDanner]

that is correct and I use a 5k ohm resistor because that is what most TPS circuits use, so I know for a fact that I am not overloading the 5v ref. circuit

[@ScannerDanner]

nice, I just checked it out. thinking about getting one myself, not for the other tests but simply for this 5v circuit tests.

[@rrmech11]

Paul Your way of wiring integrity is simple and quick. I watched other videos like realfixesreal fast and you blow them guys out of the water.Cant wait to get the e-book

[@ScannerDanner]

You can. Go to radio shack and purchase a 5v regulator. 7805 is the catalog number. It has a 1 amp max output and can be easily overloaded and ruined. You would want to run a resistor in series with it to limit current. The only problem is these circuits we are messing around with have varying amounts of resistance, so one set "in series" resistor wouldn't work in all situations. thanks Frank!

[@felplayvina]

I did jump the 5, V, R to tps in the pass, good test for me, but didn't used a resister, didn't fried nothing, next time I will used one, Thank Paul great video..

[@ceedeegutierrez]

THANK you for taking the time to make this video. Your clarity makes me want to sign up for your class.

[@ScannerDanner]

I thought so, just wanted to make sure we were on the same page. Thanks!

[@greco37]

Hello Paul-great video-on open circuits, some meters will show 0V and others will show "ghost voltage". Depends on the meter.

[@ScannerDanner]

Oh and thank you for your support! Make sure you contact me about the free video lecture offer with the purchase of the book. I just need to see the receipt and its yours. Thanks again!

[@Loyalvic89]

Thank you for an explanation of the ford 4 wire MAF, I have been searching for one, but have found very little info, not even on Mitchell. Awesome Videos!! please keep making more!

[@ScannerDanner]

For sure, because you are not exceeding the normal voltage level in the circuit. Test light works though too. I have done it many times with no damage to the PCM

[@ScannerDanner]

not a dumb question my friend. I use the term signal for inputs and control for outputs.

[@estrelladelnorte1308]

man you are good! you have no idea how much people apretiate what you do here , Thank you very much Sr !

[@ScannerDanner]

you could do that. The thing to remember, if the result of the test is not what you expect you should monitor the voltage you are sending into the signal circuit like I did. The reading you get will determine direction. Opens, shorts to ground and shorted sensors can all be options. Just think through it logically. The main point with this video was to show that circuit integrity testing has some variables and in this case why you would not want to unplug the sensor.

[@ScannerDanner]

Voltage was zero after the resistor only when I shorted it to ground. I did this to show that I am protecting the 5v ref. circuit from accidental shorts to ground. Also this is why I use a high ohm resistor. IF you used a 1 ohm resistor and there was a short to ground you would cause too much current flow on the 5v ref. circuit and potentially damage the PCM.

[@davidhall3747]

Power Probe makes an Attachment Accessory that reduces Battery Voltage to (5) Volts. It allows you to safely perform Signal Circuit Integrity Testing. Its a handy option to have- so you can work more efficiently. Thanks Paul for helping Me become proficient on Automotive Electronic Systems. I was able to successfully repair all Electrical problems on my Rolls Royce Engine. You're an effective instructor.

[@bartscave]

Although my power probe does indeed have a 5 V output, I still get nervous about using it! Probably because I haven’t used it enough yet. I still have more confidence using danners incandesent test light method.

[@ScannerDanner]

I will for sure. I have thought about making a tool to do this for awhile now.

[@jarinwilson9539]

I keep a box full of resistors in my toolbox at work. I actually got them from an electronics learning kit when I was in auto school. I'll admit it though, I've jump v-ref circuits to other circuits without using the resistors, (maybe I'm not an A+ tech) but I haven't ran into any problems....yet. Good video Paul, I'll be purchasing your book(paper version from AESwave) soon

[@GRUSSNewton]

Great job of explaining the wiring diagram Paul, very interesting info! Most MAF's on cars in the uk have the IAT built in so it's always good to have a diagram to hand.

[@ScannerDanner]

this confirms my suspicions, the MAF signal is low because the idle is low and rough, not the other way around. (a faulty MAF causing the low rough idle).

[@nunya2814]

Been dealing with 2 different maf codes on my 93 mustang, it also at one point in my 2 days of testing threw a adaptive fuel limit reached code, anyway syptoms of a bad maf were present the whole time, but id clear the codes, let the car sit an hr or so and itd run with no check engine light, after about 15-20 mins id get the light back on and crappy running. Anyway long story short the fuel pressure reg ended up have a small leak out the vaccum port, i put my stock one back in and have driven it 30 mins with no problems. Could that leaking fpr cause maf codes of voltage to low and maf sensor out of range along with the adaptive fuel limit reached. Im about to pull my hair out! lol love the vids btw, i always recommend people to watch your stuff, its awesome!

[@colingarrett7452]

Hi Paul, your videos are brilliant! I have a Ford with a no crank no start problem, I tracked down a faulty MAF using your 5v ref circuit video info. The MAF when plugged in makes all other sensors drop voltage to 3v. Unplugged MAF and they all come up to 5v. Car does not crank with the MAF unplugged so I watched this one and have decided the computer will not allow me to start without a MAF plugged in as it will have no grounds...? Am I on the right track here? I've ordered a new MAF and hope this will sort out the problem. Thanks again for such informative and watchable videos... you are THE MAN!

[@ScannerDanner]

ken, put the factory injectors back in this engine! Here is when you put bigger injectors in. You have added a supercharger to an NA engine, you have had the PCM fuel map modified (reprogram), then you put bigger injectors in that ARE PART OF the reprogram. This is when you also modify the intake and exhaust. You CANNOT modify the intake (when it doesn't need it) and add bigger injectors and expect performance gains. It just doesn't work that way.

[@sivucit]

Paul, thanks for your effort, I am not criticizing, just my 2 cents.. to make it more better.

[@ScannerDanner]

I figured it was something like that. You've inherited a problem that someone else built into it. Sorry if I sounded harsh in my responses I just don't have patience for all of the false advertising that is done in my field. We are sold these products claiming these performance gains and they only tell us half the story. The engine must be modified FIRST! They don't tell you that.

[@dyenasty08]

On the 5v generator. The power probe hook is awesome for that. I just picked one up.

[@ScannerDanner]

sounds good, let me know. My guess is that you will find severely negative fuel trim numbers. Is the idle rough?

[@33798]

Explained with your drawing so great ❤️

[@JoeNunes345]

Great video Paul. You made it look very clear and easy to understand. Keep up the good work. Thank you.

[@rexluongo6470]

I thought your drawings were great and very good illustration of what happens when you disconnect the connector to the MAF sensor and create and open ground in the circuit. Good job! Technically when two wires or circuits cross your supposed to put one at a rectangle shape to show that they do not connect, notice I didnt say touch?, on the same circuit but I know you know that and skipped it in the interest of speed to show an example.

[@ScannerDanner]

and you won't. the only time you would need to be concerned would be if the signal wire is shorted to ground. so you would be shorting the reference wire to ground in that case and that isn't a good thing. although these 5v ref. circuits are protected internally by the PCM

[@ScannerDanner]

Thank you so much! I still have a lot to learn myself though

[@nathanwright850]

Paul if you were to unplug the maf sensor and ground the harness (pcm neg and the maf neg )woud the pcm now show the 5 volt signal integraty voltage that you normaly show when you unplug the other types of sensors

[@ScannerDanner]

that part I cannot answer. I haven't played around with it enough. In short it would need to be variable. The reason I use a 5kohm for some of my tests is this is the typical resistance of most TP sensors. Also remember that in most cases you can use the existing circuitry for integrity testing and you do not need to do this. Check out my video titled "signal circuit integrity update"

[@ScannerDanner]

I remember that school. Thank you!

[@robertmccully2792]

But i like the way you do not waste words.. When i go over this enough times it will get what your trying to teach. I will write it down make digrams or whatever it takes to get it and remember . My problem is that i am working on a obd 1. I have a modis but i can not have real time info.. But i found a breakout box as subsitute.. It will take longer, be harder but in the end this stuff your teaching is the inner guts... Nice Job

[@ScannerDanner]

Thank you my friend!

[@ScannerDanner]

That may work. I just bench tested one. It was 1K to 5K ohms.

[@ScannerDanner]

I haven't either and I've done it many times myself without a resistor. Just being cautious that's all.

[@ScannerDanner]

thank you Richard!

[@ScannerDanner]

perfect reply, thank you!

[@ScannerDanner]

what are your fuel trim readings at idle? STFT and LTFT

[@ScannerDanner]

It sounds to me that the MAF is working like it should. I would look for a vacuum leak or air intake leak. Remember that anything that causes the idle speed to drop will also reduce the idle MAF signal.

[@sivucit]

Hi Paul, at 16.06 you said, resistor of 5000 ohms is connected in series and u proved that by sorting the signal wire, voltage was zero after the resistor but it was 5v before the resistor.. To me, even if u have 1 ohm resistor instead of 5000 ohm u will get same result, but the fact is if u have 5000 ohm resistor in series, the current drawn in that series will be 2 milli amp, and that 2milli amp will be consumed by every node in series circuit including PCM that is why it Is safe..

[@sivucit]

Thanks, which is what I said in my note as well.

[@kenshupe1]

I purchased the car with the injectors installed already my sons dumb Choice Kids LOL.I had a feeling you were going to tell me to put 19lb ers back in.BBK was telling me it should run with the cal mass air.Im tired of beating my head up on this.Finding stock injectors and putting it back stock to end issues. Thanks Again

[@jmac2050]

thinking you can use a test-light as your safety resistor if you don't have a 5k resistor handy

[@ScannerDanner]

Exactly, I've since experimented with that and a regular style incandescent test light does work as a safety measure. I took a 5v ref straight to ground through it and the ref circuit stayed at 5 while the bulb glowed simply. I measured current flow too but don't remember how much it was.

[@marciopocciotti]

Very nice video indeed. thanks a lot for the explanation!!!

[@malisa696]

Hi Paul. Great video. Have a question. Can we instead of 5 V that we take from DPFE sensor take safely from battery positive 12V for checking the signal wire? Same when we check oxygen sensor.

[@ScannerDanner]

yes

[@kenshupe1]

I agree, Thanks for your help

[@ScannerDanner]

Not in this application. There is no signal reference or bias voltage on this sensor. The MAF sensor generates the 0-5v signal on its own.

[@felplayvina]

I guess this test can be done on any car, maf sensor analog or digital? this test is like the TPS and if I have 5V ref next to my signal I just can use the resistor..

[@erickvqz77]

So helpfully thank you, so much thanks to your videos and you e book I been learning a lot

[@Z14kt12timandjes1]

That was awesome! I love how you borrowed 5V from another sensor. How efficient! Had I not seen this video, I probably would have rigged up some sort of a cell phone charger to get that 5V from. 👴

[@davakil]

Hi Paul at about 5 minutes minutes into it when you connected the resistor on the left side (5v ref side )not in series and you grounded it to the battery with a jumper wire (shorting out the references)I was surprised that it didn’t burn something and it stayed a 5 v can you please explain

[@estrelladelnorte1308]

let us know if you build that gadget dude! i would like to see it . could you use a potenciometer with the same values instead of the TP?, aren't they esencyally the same thing?

[@pigeonsil240sx]

could i make a 5v reference tester if i get a 12v to 5v usd cigarette lighter male plug and smply find a usb cord that plugs into that usb port/cut the wire to find the 5v power freed and ground in my newly made usb wire and use my typical 0.15a-0.20a test light to look for problems? would this me a safe viable method for testing 5v ref?

[@killertinytot]

great videos I've subbed. first thoughts on this, l200 new maf plugged in sputters and won't rev. disconnected runs great. no trouble codes. can't find anything on this

[@roro560v8]

You are the man , pls keep it up

[@rcchar]

Can you unplug the MAF and ground the PCM negative to test the wires?

[@ScannerDannerPremium]

+Randy Charlton yes you can. Good question!

[@trainer2018]

Mr. Danner, do you have any info for a 6 wire MAF? I have a good peak voltage on it but my graphed frequecy is showing dropouts from a 20k hertz peak and then when I open the throttle steady the frequency drops to almost nothing and the engine sounds fine. I only notice the rough running during idle and the frequecy drop outs. This on a 2006 Ford Ranger 3.0 six.

[@efrencerda5459]

Thank Paul,., great explanation,.,!!!

[@felplayvina]

Hello Paul question 04 vw Jetta 2.0L maf signal problem at idle have 1.40v but the signal have small waveform, history this car have been running for few moth with bad maf sensor, today it been replace 2 time with after market sensor, sensor plug or unplug 0.02 ma I jump the 5 ref with resistor close to 5 at signal, test light connect to B positive no lighting.

[@redsson6669]

last thing paul, what OHM resistor should i use? ''for the 5v regulator''

[@ozzstars_cars]

i LIKE it, thank you

[@Pdubforever1]

your teaching methods👍👍👍

[@ScannerDanner]

Thanks!

[@83VF750F]

Thanks for the video!!! Stephen

[@derekoliveira7446]

Do you think this test is more secure than the testeligth connected to the battery?

[@ScannerDanner]

Let me know if you need more information about our school and if you wanted someone to contact you. Thanks I would love to have you in my class!

[@estrelladelnorte1308]

how about using what paul says and wire in series a TP sensor ( feed your 5volt generator output 5 volts to the imput 5 volts of the TP sensor, and use the tp sensor as a variable resistor by turning with your hands, that would be your variable resistor in series, you think that might work?

[@javiersolis4072]

HI PAUL I HAVE ONE QUESTION CAN IT BE DONE THE SAME TEST WITH A TEST LIGHT?

[@MrHondaMan83]

Paul, I've got a question about 5v ref. voltage and 5k resistor. I watched a comment on ADP Training and there was that 5k resistor is useless because the communications network goes down if 5v ref. shorts. The question is, what happens in this case and is it still safe to do without the 5k resistor? I mean that can you really fry the ECU or is it just a precaution and have you ever fried? What happenns if the sensor shorts the 5v ref., then it would fry the ECU?

[@ScannerDannerPremium]

The com. circuit will go down if the ref. circuit is shorted. The reason I suggest a 5kohm resistor is in case the SIGNAL circuit is shorted to ground. So you do not accidentally pull the 5v ref. circuit to ground when doing integrity testing. Make sense?

[@Alexvr01]

i have a six cable ford maf. does it makes a difference or is it true that the 2 cables situated on the adges are not used? nice video!

[@ScannerDanner]

it does matter, and they are used. The other two wires are for an intake air temperature sensor. The testing methods however shown in this video would be identical

[@Alexvr01]

thank u so much Mr. danner i have subscribed your channel and liked the video. keep it up!

[@derekoliveira7446]

Hello Paul, I want to ask you if I can use ref. 5volts of another sensor and the resistor 5000ohms to test for example TPS and MAP sensor?

[@JSchwaderer]

great video, I have a question for you. My sisters 2001 f150 with a 5.4. I have 12v going to maf sensor but I cannot generate the 5 volts like you did here. The scanner only with read 0.01 when added the 5 volts. Did the ground test with ohms and pcm ground was 40.5 resistance.. Does this mean the pcm is bad?

[@JSchwaderer]

I mean ecm...

[@ScannerDanner]

No! That test should be done plugged in. Backprobing the signal circuit. Was it?

[@JSchwaderer]

@@ScannerDanner I tried unplugged. I tried testing it also with running on the signal wire and the signal ground and could only get like 224 milli volts. I still think the ecm is fried. Because I cannot get any voltage on my scanner for the maf sensor. shows 0.00 even at high idle..?????

[@rogermartin2176]

Hey Scanner Danner,When I unplugged my MAF sensor instead of getting 0.00 volts I’m getting .23?

[@ScannerDanner]

that is just open circuit voltage you are seeing, not a problem

[@kenshupe1]

thanks a million!I will let you know

[@ScannerDanner]

It isn't necessary to do this on these other sensors (and I don't think it would work). Most of them, the integrity of the signal circuit can be easily verified by simply unplugging the sensor. While others you would jump the reference wire to the signal wire with a resistor. Check out my video titled "signal circuit integrity update"

[@marinkojezabek2555]

If they're running that second earth wire back through the maf sensor and then down to the block, wouldn't that create more interference/noise on the circuit. Many sensor circuits are grounded through the PCM to prevent this are they not ?

[@ScannerDanner]

a question for the engineer my friend. All I can say is the MAF chip in the engine computer grounds through the MAF sensor itself. The ECM will NOT respond to any type of bypass testing on the signal wire with the MAF unplugged because you've taken the PCM MAF chip or sensing circuit ground away.

[@ScannerDanner]

Are we safe to use it? yes. Do we need to use it in every 5v reference type circuit? No. Check out my video on "signal circuit integrity update for my eBook"

[@TheManny4692]

AWESOME VIDEO!!

[@kenshupe1]

will computer relearn to compensate for larger injectors long as o2s are working properly.

[@monirobaid5809]

Hi, I am in the process of repairing the mass air flow sensor connector wiring. As a result of the mice messing around, I cut the wires off the connector side, leaving approximately two inches for each wire attached to the connector. I thought each wire was a different color, but I was surprised to find two wires of the same color. I drive a 2006 Infiniti M35 with a maf sensor that has 5 wires in this order from left to right: red, black/white, white, yellow/green, black/white, so I connected the 3 different colored wires and was left confused about the two Of the same color. I tried connecting this to this and vice versa and I did not feel any difference. I also tested them with a multimeter and they both gave the same measurement. So if you have any idea or suggestion that can help, I would be appreciative. thank you

[@ScannerDanner]

You should have a 12v feed, a MAF signal wire, a MAF ground, an intake air temp sensor signal and an intake air temp sensor ground. The IAT wires can be mixed up, but nothing else can

[@monirobaid5809]

Thank you for your response, Mr. ScannerDanner. I have been following you for nearly seven years, since I started relying on myself to maintain and repair my cars. I found you to be the best person on KZbin for diagnosing and explaining electrical problems. In the past, I have used a few of your videos to diagnose and repair my cars, but I did not understand what you mean. Is it possible, please? Clarification

[@ScannerDanner]

​@@monirobaid5809you should also be able to find a diagram with pin numbers that are labeled for which circuit. Bet you could Google that. What did you need clarification on?

[@derekoliveira7446]

If with a plug off and a jumper wire connected to ground, so can t we testing now since the ecm already has ground?

[@waynebolton1348]

Can you tell me why put on 1 scanner worked then went out and no fuse is blown what's the problem .he told me it was cig lighter was out but no fuse blower got me puzzled yes it's the 1994s10 vortec 4.3 w

[@ScannerDanner]

give it a few, it will be, i just uploaded it

[@luffakft]

2002 Ford Explorer, MAF senzor signal circuit 4.95V, but after start the engine drop down 2.83V, reference signal 1,2V-1,48V not more, and the engine max 2000rpm and no more, do you think the 2.83V is ok? Need I do something whit it? thank you for your answer

[@ScannerDanner]

No. It should be just over a volt at idle and up to 4v at wide open throttle

[@luffakft]

Guess, what is the problem? Maybe....? Thank you.

[@estrelladelnorte1308]

no problem :)

[@johnnymalicoat754]

Is this maf not a 5v pull down ckt? The way i thought i understood it was you would have 5v on the signal ckt and you would pull it to ground with my test light to battery ground and watching my scan tool

[@ScannerDanner]

This is not. The sensor generates an analog 0-5 volt signal. Sensor unplugged you will have 0v on the signal wire on this design.

[@johnnymalicoat754]

Wow there is so many different systems. Thanks for all the information you put out and responding to my questions.

[@johnnymalicoat754]

Like a non hall effect cam or crank sensor?

[@fulgenciomarcos1696]

I like it

[@markkouros6628]

Does a bad or cheap map sencor stop car from starting, my car has black spark p plugs during process

[@ScannerDanner]

MAP or MAF? This video is on a MAF sensor In either case, unplug it and see if it starts. If it still doesn't, that isn't your problem EDIT: Without knowing what you are working on there are some variables to that test

[@markkouros6628]

@@ScannerDanner cheers buddy great work , wound up being injectors I tried to upgrade to 4 port no good 🍻 94 Fairmont..

[@sivucit]

Yes ..

[@ScannerDanner]

to an extent but the answer is no. you need to put the correct injectors back in this un-modified engine. All you are doing is causing problems and wasting fuel. You will NOT get any performance gains from this set up. All you will do is melt down your cats, fuel contaminate your oil, increase piston ring wear, cause fuel trim and O2 related codes, etc., etc.

[@StreetBikeTakeoverYT]

tindydx95t2 ..I agree.. he explains things a LOT better than my teacher did, keep the videos coming if you can I watch them everyday :D